1. Field of the Invention
This invention relates to Mannich condensates prepared from an alkyl phenol, formaldehyde and polyoxyalkylene diamines, as hereinafter defined.
More particularly, this invention relates to initial Mannich condensates prepared by reacting an alkyl phenol with formaldehyde and a first polyoxyalkylene diamine to provide an intermediate paired alkyl phenol Mannich condensate which is further reacted with formaldehyde and a second polyoxyalkylene diamine, as hereafter defined, in order to provide a paired final Mannich condensate of the present invention.
The intermediate Mannich condensates and the final Mannich condensates are useful as epoxy resin curing agents.
2. Prior Art
The Mannich reaction is a well-known reaction which has been extensively reviewed in the literature. See, for example, "The Mannich Reaction", Org. Reactions 1, 303 (1942) and "Advances in the Chemistry of Mannich Bases", "Methods in Synthetic Organic Chemistry-Synthesis", Academic Press, pp. 703-775, 1973.
Brennan et al. U.S. Pat. No. 4,485,195 discloses Mannich condensates prepared by reacting an alkyl phenol with formaldehyde, diethanolamine and a minor amount of melamine to provide products which can be alkoxylated for use in the preparation of fire retardant, rigid polyurethane foams.
Other Mannich condensates prepared by reacting alkyl phenols with formaldehyde and alkanolamines and melamine are disclosed in Brennan et al. U.S. Pat. No. 4,487,852, Brennan U.S. Pat. No. 4,489,178 and Brennan U.S. Pat. No. 4,500,655.
Waddill et al. U.S. Pat. No. 4,736,011 discloses Mannich condensates prepared by the reaction of an imidazole with formaldehyde and a polyoxyalkylene polyamine which are useful as curing agents for epoxy resins.
Becker U.S. Pat. No. 3,734,965 discloses phenolic resins prepared by condensing a polyoxypropylenepolyamine with phenol and an aldehyde.
Grigsby et al., in U.S. Pat. No. 4,714,750, describe the Mannich condensates prepared from 2,6-di-t-butylphenol, formaldehyde and a polyoxyalkyleneamine, i.e.: ##STR3## where: R=H or CH.sub.3, and n=1 to 20.
Cyanoethylated derivatives of polyoxyalkylenepolyamines are disclosed in Rowton U.S. Pat. No. 3,666,788 and polyureas prepared by reacting the cyanoalkylated polyoxyalkylenepolyamines with an isocyanate are disclosed in Rowten et al. U.S. Pat. No. 3,714,128.